Do the following:
Capture a footage in HD.
Capture the same with downconvert to SD option.

The timecode is shifted. The same frame does not have the same timecode in HD and SD. Any comments?

This is normal and common. TC is generated over 12 frames, like the mpeg-2 image.
Had the same problems with the Z-1. Edit natively in HDV or, if you can capure HDV and export rom your apllication to SD (FCP exports the timecode as well. But you will use double disc space.
Cheers,
Salar

How far off is the timecode when downcoverting. I do same day highlights at weddings and when we do one with the new A1 we will be downconverting. We have a shot list and write down timecodes of shots we want so we can capture more easily. Is it many seconds or just a few frames of a second?

How far off is the timecode when downcoverting...
About 11-12 frames.

Cool....I can deal with that. Our timecodes just get us in the ball park of where the shot was at. If it was multiple seconds it may cause a problem.

Not sure if this is related or not... When capturing down-converted footage using Scenalyzer Live, using time-code changes to detect scene breaks, I consistently get 3 frames from the previous scene on the front of every clip. This is just a little confusing in my NLE (Liquid 5.62) since by default it uses the first frame as the icon thumbnail picture (they call it a "picon") for the clip. If this was a GOP issue, I'd expect a varying number of extra frames, from 0 to 13 (PAL GOPs are 13 frames). I therefore think that in the data stream over firewire, the timecode is 3 frames ahead of the pictures. Has anyone else noticed this? Maybe it is a result of using Scenalyzer? I must try capturing with Liquid, and see if I get the same result....

I use Adobe Premiere CS 2.0